Automatic reassignment of a telephone number of a wireless terminal based on location of the wireless terminal

ABSTRACT

When a wireless terminal enters a new location, the telephone number assigned to the wireless terminal is automatically changed to be a telephone number assigned to that location. The features associated with the wireless terminal will also be changed to the features assigned to the location. In addition, this invention allows flexibility for the telephone number of the wireless terminal to remain fixed and not to be changed to a telephone number assigned to a particular location.

TECHNICAL FIELD

This invention relates generally to wireless switching systems and, in particular, to the assignment of telephone numbers.

BACKGROUND OF THE INVENTION

In the modern business environment of today, individuals have different responsibilities and work in different job locations that change on an hourly basis or a daily basis. For example, an individual may be a secretary working at a particular desk for part of the day and a librarian working in a corporate library for the remainder of the day. In addition, within a department store, an individual may work in the shoe department for part of the day and work in the household department for the remainder of the day. At present, each of these departments has wired telephones which are permanently stationed in each of the areas where an individual may go to work. Department stores and many other businesses publish to their customers and clients the internal telephone number that may be dialed by an outside individual to reach a particular department. For example, a customer of a department store wishing to call the houseware department simply dials the direct number for that department.

With the advent of wireless telephones, companies have been forced to dedicate wireless telephones for each particular department having the telephone number assigned to that department. This presents many problems for companies. For example, a common problem is for an employee, after their shift is completed, to leave the department still carrying the wireless telephone; hence, the dedicated wireless telephone cannot be utilized by another employee coming on for the next shift. In addition, it is hard to determine precisely how many dedicated wireless telephones are needed for each particular department. Furthermore, if an employee comes into a particular department to lend temporary assistance for a matter of minutes, they must try to find a dedicated wireless telephone assigned to that department.

SUMMARY OF THE INVENTION

This invention is directed to solving these and other problems and disadvantages of the prior art. According to the invention, when a wireless terminal enters a new location, the telephone number assigned to the wireless terminal is automatically changed to be a telephone number assigned to that location. Advantageously, the features associated with the wireless terminal will also be changed to the features assigned to the location. In addition, this invention allows flexibility for the telephone number of the wireless terminal to remain fixed and not to be changed to a telephone number assigned to a particular location.

These and other features and advantages of the present invention will become more apparent from the following description of an illustrative embodiment of the invention considered together with the drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a block diagram of a wireless system for implementing the invention;

FIGS. 2 and 4 illustrate a table that is maintained by a wireless switching system defining the relationship between the physical identification number of a wireless terminal and its assigned telephone number;

FIG. 3 illustrates a table that defines the telephone numbers assigned to each location;

FIGS. 5 and 6 illustrate, in flow chart form, steps performed by a wireless switching system;

FIG. 7 illustrates, in block diagram form, a fixed unit;

FIG. 8 illustrates, in block diagram form, a wireless terminal;

FIG. 9 illustrates, in flow chart form, steps performed by a wireless terminal; and

FIG. 10 illustrates, in flow chart form, steps performed by a fixed unit.

DETAILED DESCRIPTION

In FIG. 1, switching system 111 provides wireless service for wireless terminals 112-114 via base stations 121-122. Wireless switching system 111 is interconnected to public telephone network 118 via link 117. Wireless switching system 111 determines the location of a wireless terminal in the following manner. The location is designated with the same number as the fixed unit identifying that location. For example, fixed unit 101 provides the location information for location 101. A fixed unit transmits a signal at predefined intervals defining the identity of the fixed unit. This transmission occurs on a different transmission medium than that utilized by the wireless terminals to communicate with the base stations. For example, when wireless terminal 112 enters location 103, it receives the identification information defining fixed unit 103. Upon receiving identification information defining a new fixed unit, wireless terminal 112 transmits a data message to wireless switching system 111 and inform wireless switching system 111 that wireless terminal 112 is now receiving the identification information from fixed unit 103. Wireless switching system 111 then identifies that wireless terminal 112 is in location 103. One skilled in the art could readily see that other methods could be utilized to determine the location of a wireless terminal. For example, the wireless terminals could transmit identification information defining the wireless terminal to a fixed unit which then could relay this to wireless switching system 111 via wired or wireless media to wireless switching system 111. In addition, global positioning satellite (GPS) devices or base stations could be used to determine a position of a wireless terminal.

In accordance with the invention, when wireless switching system 111 receives information from wireless terminal 112 that it is in location 103, wireless switching system 111 updates table 1 illustrated in FIG. 2 to assign telephone number 538-3901 to wireless terminal 112. In addition, the table 2 of FIG. 3 is updated to reflect that that telephone number is assigned to wireless terminal 112. Both Table 1 and Table 2 refer to the wireless terminals by designation numbers as illustrated in FIG. 1 for convenience of description. In actual implementation, the serial numbers of wireless terminals would be used instead of the designation numbers. A wireless terminal has a 12 digit serial number that is used to identify the wireless terminal to wireless switching system 111. The serial number is transmitted with each message to wireless switching system 111.

Consider now the example, where wireless terminal 112 moves from location 103 to location 104 via location 101. When wireless switching system 111 is informed by wireless terminal 112 that it is now in location 101, wireless switching system 111 determines from FIG. 2 that the assigned telephone number for wireless terminal 112 is not to be modified when the wireless terminal enters location 101. Consequently, wireless switching system 111 does not modify the current telephone number illustrated in Table 1 of FIG. 2 for wireless terminal 112. Further, consider when the wireless terminal moves to location 104. Upon being informed that wireless terminal 112 has entered location 104, wireless switching system 111 examines Table 2 of FIG. 3 for the telephone numbers assigned to location 104 at present, telephone number 538-1901 is assigned to wireless terminal 114. Hence, wireless switching system 111 assigns telephone number 538-1902 to wireless terminal 112. Table 1 of FIG. 2 is updated to reflect this change and the updated table is illustrated in FIG. 4. In addition, Table 2 of FIG. 3 would be updated to reflect the fact that wireless terminal 112 is now assigned telephone number 538-1902. If wireless terminal 114 had not been present in location 104 when wireless terminal 112 entered location 104, wireless terminal 112 would have been assigned telephone number 538-1901. Table 2 of FIG. 3 will also be updated to reflect the fact that telephone number 538-3901 is no longer assigned to wireless terminal 112.

Since wireless terminal 112 has been assigned a new telephone number the features associated with that telephone number now are provided to wireless terminal 112 by wireless switching system 111. When a call is received from public telephone network 118 for telephone number 538-1902, wireless switching system 111 examines Table 1 of FIG. 4 and determines that the call should be routed to wireless terminal 112. One skilled in the art would readily recognize that the telephone numbers illustrated for each individual location in Table 2 would be placed in a hunt group by wireless switching system 111. Such a hunt group would allow a telephone call directed to a first number for a location to subsequently be transferred to a second number of the location if the first number of the location was busy.

FIGS. 5 and 6 illustrate, in flowchart form, the steps performed by wireless switching system 111 in implementing the invention. Decision block 501 determines if there is a message from a wireless handset. If the answer is no, control is transferred to block 502 which performs normal processing before returning control back to decision block 501. If the answer in decision block 501 is yes, decision block 507 determines if a “no fixed unit” message is being received from a wireless telephone. Such a message indicates that a wireless telephone is not receiving the transmission signal from any fixed unit. If the answer is yes in decision block 507, control is transferred to block 504 which determines the last known location. Wireless switching system 111 maintains a list of last known locations for each of the wireless terminals. Block 506 then signals that the wireless telephone cannot receive a fixed unit around the last location listed for the wireless telephone. This signaling may be in the form of a message displayed to an operator of wireless switching system 111 or merely a message being included in a maintenance log of wireless switching system 111. After execution of block 506, control is transferred back to decision block 501.

Returning to decision block 507, if the answer is no, decision block 508 determines if a low battery indication was included in the message identifying the fixed unit from the wireless telephone. If the answer is no in decision block 508, block 509 determines the location based on the identification code of the fixed unit of the wireless telephone before transferring control to decision block 601 of FIG. 6. If the answer in decision block 508 is yes, the low battery indication for the identified fixed unit is placed in the database, and a maintenance message indicating low battery is generated before transferring control to block 512. Block 512 performs the same operations as block 509 before transferring control to decision block 601 of FIG. 6.

After the determination of the location of a wireless terminal has been made in either block 509 or 512, control is transferred to decision block 601 of FIG. 6. The latter decision block determines if the location of the wireless terminal has changed by examining Table 1 of FIGS. 2 or 4. If the answer is no, control is transferred back to decision block 501 of FIG. 5. If the answer in decision block 601 is yes, control is transferred to decision block 602 which examines Table 1 of FIGS. 2 or 4 to determine if the new location is excluded for the wireless terminal. If the answer is yes, control is transferred back to decision block 501 of FIG. 5. In the previous example, when wireless terminal 112 entered location 101, decision block 602 would have determined from FIG. 2 that location 101 was excluded for wireless terminal 112.

If the answer is no in decision block 602, control is transferred to decision block 603. The latter decision block examines Table 2 of FIG. 3 to determine if there are any idle telephone numbers associated with the new location. If there are no idle telephone numbers associated with the new location the wireless terminal's telephone number cannot be changed and remains the same as for the previous location. Note, that the present location in Table 1 of FIG. 2 is not updated to reflect the new location and remains set to the old location. The next time that the wireless terminal transmits its location, decision block 601 once again detects a change in location and once again control is transferred to decision block 603 to see if there is now a idle telephone number in Table 2 for the new location. If the answer in decision block 603 is no, control is transferred back to decision block 501 of FIG. 1. If the answer in decision block 603 is yes, control is transferred to block 604 which updates Table 2. Table 2 is updated to reflect the new telephone number that is assigned to the wireless terminal and to remove the indication that the old telephone number is assigned to the wireless terminal. After execution of block 604, control is transferred to block 605 which updates Table 1 for the assigned telephone number for the wireless terminal and to indicate the present location as the new location. After execution of block 605, control is transferred back to decision block 501 of FIG. 5.

FIG. 7 illustrates in block diagram form a fixed unit. The fixed unit of FIG. 7 is powered by battery 701. However, one skilled in the art could readily see that normal building AC power could also be utilized to power the fixed unit. Controller 703 periodically transmits the identification code for the fixed unit via transmitter 704. Advantageously, transmitter 704 can be transmitting utilizing infrared transmission or ultrasonic transmission. Transmitters for transmitting either infrared or ultrasonic are well known in the art. If controller 703 detects that battery 701 is at a low power level via conductor 707, battery monitor 702, and conductor 708, controller 703 sets alarm indicator 705 and transmits the low power indication along with the identification code via transmitter 704.

Wireless handset 112 is illustrated in greater detail in FIG. 8. Wireless handset 112 implements a wireless protocol that allows wireless handset 112 to transmit data messages to wireless switching system 111 via base stations 121-122. One air interface that can be used is the Common Air Interface (CAI) specification for Cordless Telephony 2 (CT2), Release 2, I-ETS 300 131. The data message is a layer 3 message. Particularly, the data message is transported as a feature activation class 3 of the TERMCAP IE using a new value. Overall control of the wireless handset is provided by control unit 801. Units 802, 803, 806, 807, 808, and 809 provide the RF communication capabilities for the wireless handset. Elements 804, 810, and 811-814 provide the audio information received and transmitted to the user; whereas, elements 816-818 and 805 provide the basic user interface. The CT2 protocol allows control unit 801 to transmit data messages to wireless switching system 111. Control unit 801 utilizes these data messages to transmit identification information for fixed units to wireless switching system 111. Fixed unit receiver 821 receives the identification code of a fixed unit and transfers this identification code to control unit 801 for transmission to wireless switching system 111. Fixed unit receiver 821 is of a design well known in the art for either infrared or ultrasonic transmission media. One skilled in the art could readily see that fixed unit receiver 821 could provide to control unit 801 the signal strength of the received signal. Further, control unit 801 could also tune fixed unit receiver 821 to receive different frequencies or other variations of the transmission media using well known techniques in the art.

FIG. 9 illustrates the steps performed by a wireless terminal such as wireless handset 113. Decision block 901 determines if the time has elapsed to monitor for a fixed unit. Advantageously, every second the wireless handset monitors to determine if the transmission signal of a fixed unit is being received. If the answer in decision block 901 is no, normal processing is performed by block 902 before control is returned back to decision block 901.

If the answer in decision block 901 is yes, control is transferred to decision block 903 which determines if a transmission signal is being detected. If the answer in decision block 903 is no, control is transferred to block 906. The wireless handset transmits a “no fixed unit” message to the central computer by execution of block 906 before transferring control back to decision block 901. Returning to decision block 903, if the answer is yes, control is transferred to block 909. The latter block determines the identification code of the fixed unit whose transmission signal is being received, and block 911 transmits the received identification code to wireless switching system 111 before transferring control to decision block 912. Decision block 912 determines if a low battery indication was included in the transmission signal from the fixed unit. If the answer is no, control is transferred back to decision block 901. If the answer in decision block 912 is yes, block 913 transmits a low battery indication message to wireless switching system 111 for the identified fixed unit.

FIG. 10 illustrates the steps performed by a fixed unit. Decision block 1001 determines if it is time to transmit the identification code of the fixed unit. Advantageously, the identification code is transmitted every tenth of a second. If the answer is no, control is transferred back to decision block 1001. If the answer is yes, decision block 1003 determines if battery monitor 702 of FIG. 7 is indicating a low battery. If the answer is no, block 1004 simply transmits the identification code of the fixed unit before transferring control back to decision block 1001. If the answer in decision block 1003 is yes, block 1006 transmits a message that includes the identification code and a low battery indication before transferring control back to decision block 1001.

Of course, various changes and modifications to the illustrative embodiment described above will be apparent to those skilled in the art. These changes and modifications can be made without departing from the spirit and the scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be covered by the following claims. 

What is claimed is:
 1. A method of administering telecommunication numbers for a wireless terminal, comprising the steps of: determining in which one of a plurality of locations the wireless terminal is located; identifying a first telecommunication number assigned to the one of the plurality of locations; assigning the first telecommunication number to the wireless terminal further determining that the wireless terminal now is located in another one of the plurality of locations; and ascertaining that the wireless terminal is excluded from being assigned a second telecommunication number assigned to the other one of the plurality of locations.
 2. An apparatus for performing the method of claim
 1. 3. The method of claim 1 further comprises the step of retaining the first telecommunication number assigned to the one of the plurality of locations in response to the step of ascertaining that the wireless terminal is excluded from being assigned the second telecommunication number assigned to the other one of the plurality of locations.
 4. An apparatus for performing the method of claim
 3. 5. The method of claim 3 wherein the first telecommunication number is one of a plurality of telecommunication numbers assigned to the one of the plurality of locations.
 6. An apparatus for performing the method of claim
 5. 7. The method of claim 5 wherein the step of determining further determining that another wireless terminal is located in the one of the plurality locations: identifying another one of the plurality of telecommunication numbers assigned to the one of the plurality of locations; and assigning the other one of the plurality of telecommunication numbers assigned to the one of the plurality of locations to the other wireless terminal.
 8. An apparatus for performing the method of claim
 7. 9. The method of claim 7 wherein the step of identifying comprises the step of accessing a table defining telecommunication numbers for ones of the plurality of locations.
 10. An apparatus for performing the method of claim
 9. 11. The method of claim 9 wherein the step of ascertaining comprises the step of accessing another table defining ones of the plurality of locations whose telecommunication numbers are excluded from being assigned to the wireless terminal.
 12. An apparatus for performing the method of claim
 11. 13. The method of claim 11 wherein the step of determining comprises the step of transmitting location information by the wireless terminal to a wireless switching system that provides telecommunication service for the wireless terminal; and providing the one of the plurality of locations in response to transmitted location information by the wireless switching system.
 14. An apparatus for performing the method of claim
 13. 15. The method of claim 13 further comprises receiving the location information by the wireless terminal from a fixed unit within the one of the plurality of locations.
 16. An apparatus for performing the method of claim
 15. 